Fermenting method



2 Sheets-Sheet 1 Filed April 27, 1944 uvmvroa .imiz lr May 4, 1948;

B. C. BOECKELER FERMENTING METHOD Filed April 27, 1944 2 Sheets-Sheet 2 IN VEN TOR.

rnmmnrmo Iim'rnon Benjamin Clark lBoeckeler,

by mesne assi to Chemprotin Produc ited partnership of Michigan,

signer,

Grosse He, Mich, as-

gnments, of 9,448/10570 ts, Trenton,

Mich, a lim- 561/10,570 to Laszlo Kormendi, and 561/10,570 to B. Clark Boeckeler Application April 27, 1944, Serial No. 533,036

This invention relates to cedures and is herein illustrated as embodied in fermentation pro- 2 Claims. (01. 195-13) factor creates serious limitations upon the ultimate efilciency of the overall process of producing alcohol from starchy material, such as grains and from sugars, such as contained in cane syrup, molasses and converted starch.

It has hitherto been attempted to increase the efilciency of the process by increasing the efiiwhole could be successfully According to one form of the present invention, the usual batch fermentation process is altered in a continuous or quasi-continuous over a much longer period found possible.

The invention is embodied in removing the alcohol by distilling but also alternative methods are described acdescribed in some detail as frigerated so as ceiver 2! provided at the top wit '2 apparatus including devices for continuously removing alcohol during the fermentation procedure.

Fig. 2 diagrammatically shows a fermentation apparatus, in which the fermenting material is passed through successive fermenters is removed between them. 7 r

Fig. 3 diagrammatically shows removal of alcohol from a fermenter during the fermentation therein.

In the form shown in and alcohol Fig. 1, a fermenter vessel N3 is charged with the starch or grain or sugarcontaining material and water and other suitable ingredients, including yeast, through a valved pipe line i I, and carbon dioxide produced in the fermentation leaves through a valved vent i2.

After fermentation has processed for some time, alcohol begins to build up in the mash or liquor contents of fermenter l0, and, when a suitable concentration has been reached, part of pumped into a stripping tower l5, which is only conventionally shown.

A vacuum is maintained of suitable amount for commercial work, as by a jet vacuum conventionally shown at It, and the temperature in the tower I 5 is maintained by a coil i! at a point low enough not to kill the yeast during distillation, that is, not far from 98 F.

At that temperature the liquid coming from the fermenter will not be above 98 F. and may contain 4% of alcohol. The upper part of the tower may be maintained at 34 mm. mercury, absolute, and vapors of 35% alcohol may flash off, reducing the temperature to F. Further stripping would remove more alcohol as the liquid flowed down over the six stripping decks l5a. Theoretically, the complete removal of alcohol at a temperature of 98. F. in the bottom of the stripper would involve a pressure of 46 mm. of mercury there.

The alcohol thus distills off, along with water vapor and some air and carbon dioxide, through the top pipe is and enters a condenser l9 reto condense the alcohol vapor. The vacuum device at I6 draws along through the valved-exit pipe 20 the condensed alcohol and air and carbon dioxide, delivering the liquid to a rethe vacuum jet I6, and kept at a low enough temperature to substantially retain thecondensed alcohol which is drawn 011' as desired by a valved pipe 22 for redistillation.

The remainder of the liquor nearly freed from alcohol in the tower I 5 runs through a pipe 23 which may ibe high enough to maintain a suitable vacuum in the tower by a liquid column, and is iving tank 24.

delivered to a rece From the tank 24, a pump 25 is shown as realters the valves or ceiver 33, from which Moreover, mash, or any 3 turning the stripped liquor to the fermenter ll through a pipe 28.

At the conclusion or a run the residual mash is shown as withdrawn through a valved bottom outlet 21.

I! it is found desirable to make up air or carbon withdrawn by the tower II, either or both may be provided through a valved intake 28 or 29 provided with diagrammatically shown internal extensions 30 adapted to be so set as to deliver the air or carbon dioxide either above or below the surface of the mash. at will. to control the operating conditions. More mash may be added, as desired, through the pipe H, of suitable water and solid content tomaintain the desired conditions.

According to the above procedure, the operator operates the pumps to start the continuous separation of alcohol at will, and to stop it at will, returning the stripped mash to the fermenter, and positively controlling the operation.

Fig. 2 shows an alternative structure and procedure in diagrammatic form, omitting many minor pipes and other parts. Fig. 2 the first fermenter Ill may be provided with the valved outlets and inlets H, II, 21, 2| and 20, and these carry or pump the mash a continuously but slowly through a pipe II by a pump i3 to a first stripping tower I! which distills oif alcohol to be carried of! by a pipe II which also maintains a vacuum and leads to an alcohol recovery device or system and, desired. to a separate vacuum device. The strip ed mash residue flows through a bottom pipe 32 to a reit is dra'wn by a pump a and sent on to a second fermenter 35 where fermentation again flourishes by reason 0! the removal of. the deleterious amounts of alcohol.

The mash in the second iermenter 35 is similar- 1y adapted to be withdrawn when excessive alcohol is present, the fermenter 35 for this purpose having an exit pipe 36 through which the mash is shown as drawn by a pump 31.

The withdrawn mash is sent on by the pump 31 to a stripping tower 38 where alcohol is seam removed while the residual mash flows through a bottom pipe 39 to a receiver l0.

If desired, the mash in the receiver 40 is sent on by a pump ll to a third rermenter 2 in which fermentation again flourishes by reason or the removal of the deleterious amounts or alcohol. The mash in the third fermenter 2 after sumcient fermentation may be withdrawn by a pump 43 and sent on to a stripping tower M which removes alcohol, as in the two towers I! and 80. and the mash is delivered to a bottom receiver 45 and pumped on for further fermentation or to other treatment by a pump 48.

It is possible to operate the whole system of fermenters i0, 35, 42, and their connections continuously by slow flow or mash. or intermittently in batches, in any event drawing 01! and recovering further alcohol by vacuum at each tower I5, 38, 44, so far as desirable. at a temperature proper to keep the process functioning smoothly.

One advantage of the above described processes is that they require no specially built Iermenters to withstand the pressure which would bear upon them if a vacuum were maintained within them. deslred'composition, and

air or other materials, may be added at each rermenter to utilize the yeast and other materials present to the best advantage.

Fig. 3 shows another alternative structure employing a termenter which is strong enough to withstand the outside pressure resulting from a vacuum.

The fermenter S0 is shown as having a valved outlet 5| at the top which is connected by a pipe 52 to a condenser 53 having a delivery pipe 84 leading to a receiver 55 for alcohol. To the receiver 55 is connected a second top pipe 5. ending in a valved vacuum device 51, shown as a steam let, to obtain and, if desired, maintain a vacuum on the rermenter III.

little at a time. or

To replace, it need be, air or carbon dioxide to foster fermentation there are shown a valved inlet 58 and a valved carbon dioxide inlet 59 with internal extensions adjustable to deliver above or below the mash surface. There is also shown a valved feed inlet 62 and a valved drain i I Thus it is possible to operate the iermenter 50 either under a continuous vacuum, or under an intermittent vacuum. varying conditions by air and carbon dioxide feed either continuously or intermittently at will. it desired.

A fourth alternative avoids the use or a vacuum, but removes, continuously or intermittently a part of the fermenter contents. removing the contained alcohol to a considerable degree by agitating with a solvent immiscible with the water, separating from the mash the layer or solvent-carrying alcohol, and either returning the removed part with a greatly reduced alcohol content, or separately continuing the fermenting alter the alcohol is thus removed.

The complete procedure involves removing the immiscible solvent from the alcohol, usually by distillation and re-using the immiscible solvent.

Some oi the solvents miscible with alcohol but substantially immiscible with water are; n-butyl ether, dibutyi phthalate, n-hexanol, octyl acetate, octyl alcohol and trlchlorethylene.

The method of the separation of the layer of mash from solvent-carrying alcohol will depend on the specific gravity or the immiscible solvent and on other physico-chemical conditions as are well known to those skilled in the art.

The various vacuums have been diagrammatically shown and described as maintained by steam Jets, as the simplest efllcient means of maintaining a vacuum. The process may be perhaps more economically worked as a whole it the vacuum in Fig. l, for example, is maintained by a pump between the stripper l5 and the condenser is to work at higher, say an atmospheric pressure, instead of under a high vacuum. This avoids the needtor the vacuum steam nozzle 16.

Under many conditions it may be more economical to recover the alcohol at l9 by a preferentially active adsorbent, such as activated carbon, which avoids some problems of dealing with the associated air and carbon dioxide.

Alter such removal of alcohol the carbon dioxide may be recovered in any suitable manner,

and the alcohol separated from the adsorbent by any known or desired procedure.

A pump. like Dump Bl. may maintain the vacuum instead of a steam jet in each of the systems shown, and thus enable the alcohol to be condensed under any desired pressure instead of from a high vacuum in the strippers i5, 38 and 44.

It is possible to so operate the process of the present invention so as to greatly reduce the amount of inert water to be disposed of, and to obtain other advantages.

In the ordinary fermentation procedures the 7s fermenting material, sugar or starch, for examing any of its advantages. that all matter herein is pie. is charged at such a concentration that it will be completely fermented when the alcohol produced has reached or 12% alcohol content, because that content is the maximum alcohol strength in which the yeast can survive or can endure.

This means that at the end of the usual ferentlng operation it is necessaryto evaporate most of 7 to 8 volumes of inert water to separate the water from the distillers residue to make the residues salable.

According to the present invention it is possible to add fermenting material such as starch or sugar to the fermenter while distilling oil alcohol, thus obtaining several advantages in addition to, in efi'ect, eventually incorporating in a single batch all the distillers residue' from all the fermenting material added.

One of these additional advantages arises from the larger production of alcohol and of distillers residue" menter.

Another of the additional advantages arises from the continuous use of the'same yeast in long continued fermenting, thus avoiding much of the usual loss of the iermentable material which is consumed in manufacturing the new yeast cells hitherto needed for every added batch of fermentable material.

A third additional advantage arises from the high concentration of yeast cells maintained in the fermenter with the result that a high rate of alcohol fermentation ismaintained after the rate is once established. To put the facts another way, the same yeast acts through a number of cycles.

The processor operating the device of Figure 2 often involves the addition of fermenting material to each of the fermenters 35 and 42 at their valved inlets ii, and often involves the addition of air at their valved inlets 28, and the release of carbon dioxide by the valve pipe 29, although the pipe 29 may serve either as inlet or release pipe.

In the device of Figure 2, during a normal run all of the solids are usually removed at the pump 48. thus providing a liquid mass relativelyhigh in solids to be evaporated down to yield distillers residue, thus saving much of the fuel ordinarily consumed.

It will be seen that the vides an eifective method for the fermentation of a liquid mass to produce alcohol which permits maximum fermentation with a minimum of retardation of yeast growth. The toxic effect of the alcohol upon the fermenting organism is materially reduced. The process may be performed by changes in the present distilling equipment without excessive expenditures for new equipment.

As various changes may be made in the form, construction and arrangement of the parts and steps herein without departing from the scope and spirit of the invention and without sacrificit is to be understood to be interpreted as illustrative and not in a limiting sense.

Having thus described certain embodiments of the invention in some detail, what is claimed is:

1. A process for the production of alcohol which comprises fermenting a main body of mash with yeast to produce a'substantial concentration of alcohol, then continuously removing a part of the fermenting mash liquor, subjecting the part being present invention proobtainable from a given fer a part of the thus fermented alcohol-stripped mash liquor and subjecting the same to distillation under reduced pressure independently of the first distillation, continuously removing alcohol from the resulting fermented stripped mash liquor undergoing distillation and independently condensing the same, continuously withdrawing-the further stripped part of the mash liquor and subjetting the same to fermentation, then continuously removing a part of thefermenting further stripped part of the mash liquor and independently subjecting the same to distillation under reduced pressure to remove alcohol therefrom and independently condensing the alcohol thus distilled from the last-named part.

2. A continuous process for the production of alcohol which comprises fermenting a main body of mash with yeast to producea substantial concentration of alcohol, then continuously removing a part of the fermenting mash liquor, subjecting the part continuously removed to distillation under reduced pressure, continuously removing alcohol under reduced pressure from the part undergoing distillation, continuously condensing the said removed alcohol, continuously withdrawing alcohol-stripped mash liquor from the said part undergoing distillation to form a second body of mash liquor, fermenting the said-second body of mash liquor, then continuously removing a part of the fermented second body of mash liquor and independently subjecting the same to distillation under reduced pressure, continuously removing alcohol under reduced pressure from the part of the said fermented second body subjected to distillation and independently condensing the same, continuously withdrawing stripped mash liquor from the said second body to form a third body of mash liquor, fermenting the said third body of mash liquor, continuously removing a part of the fermented third body and independently subjecting the same to distillation under reduced pressure to remove alcohol therefrom, independently condensing'the last named alcohol and providing a slow flow of mash to each of said bodies to maintain the process in continuous operation. 1

BENJAMIN CLARK BOECKELER.

REFERENCES CITED The following references are of record in the file of this patent:

De Becze 8: Rosenblatt, "Continuous Fermentation," Am. Brewer, Feb. 1943. 

